Method and apparatus for broadcasting sound



June 28, 1932. P. M. TITUS METHOD AND APPARATUS FOR BROADCASTING SOUND Filed Feb. 21, 1928 IN VEN TOR. PAUL l7. 7771/6.

Patented June 28, 1932 PAUL M. TITUS, OF BINGHAMTON, NEW YORK AND APPARATUS FOR BROADCASTING- SOUND Application filed February 21, 1928. Serial No. 256,008.

It is common practice in the art of radio broadcasting to send out over telephone or telegraph wires, from a single station to a plurality of other stations, sound being broadcast from such single or master statlon. This arrangement is commonly known as a hook up whereby the same program is s1- multaneously broadcast through a plural ty of stations, usually of different frequencies. It will be understood of course that such a method of broadcasting is expensive due to the expense connected with leasing the wires over which the program is sent to the various stations on the hook up.

I have devised a means and method of simultaneously broadcasting the same program from a plurality of stations without the necessity of the transmission wires to the various stations and without resorting to the method of picking up a broadcast program by a radio receiving set and then rebroadcasting it from the local station, a practice which has been tried but found generally impractical.

The primary object of my invention is the provision of a means and method whereby a given radio program of any desired length is first recorded by known recording means, and a copy of such program sent to each of the local stations of a particular hook up from which the same program will be simultaneously translated and broadcast from all of such stations. In illustrating my invention, I have shown the programs recorded on cylinder records, and although this form of recording is believed preferable for broadcasting purposes, it will be understood that I do not limit myself thereto inasmuch as other recording means may be employed, such as photographically recording the sound on strips of film.

Another object of my invention is to provide a means under the control of a single or master broadcasting station, whereby the broadcasting of the same program will commence simultaneously at all of the stations on the hook up.

Still another object lies in the provision of a method and means whereby periods of interruption of the program will simultaneously occur at all of the stations on the hook up, to permit the local announcers to make their announcements.

Still another object is to provide a novel means whereby a program of any desired length may be broadcast under this system without interruption, the same being practically automatic in operation.

Other objects and advantages in details of method steps and construction will be appars.

ent as the description proceeds, reference now being had to the figures of the accompanying drawing wherein like reference numerals in dicate like parts.

In the drawing Figure 1 is a diagrammatic representation of a high frequency broadcasting device which is under control of the master broadcasting station of the hook up.

Figure 2 is a diagrammatic view, some parts being shown in detail, of the apparatus at each of the broadcasting stations on the hook up.

Figure 3 is a detail end view of a portion of the sound reproducing apparatus.

In the use of my improved broadcasting system, it will he obviously possible to include in a single hook up as many local stations at various points over the country as desired, all of which may be, and preferably are, broadcasting on the same meter frequency. This makes possible a large number of stations which can simultaneously broadcast the same program without the interference common when two or more stations are broadcasting on different but reatively close frequencies. It should be understood, however, that it is not necessary that all the stations on my improved hook up should broadcast on the same frequency.

In carrying out my invention, each of the stations to be included in the hook up are provided with the apparatus illustrated more or less diagrammatically in Figure 2. This apparatus includes primarily a broadcasting unit 1 of a given frequency, controlled and operated by well known means. Each station is likewise provided with preferably two sound record translating machines indicated generally as 2 and 3, each provided with an manner.

electric motor 4 and 5 equipped with driving means 6 and 7, whereby mandrels, upon which are removably mounted the records 8 and 9 may be rotated. These records 8 and 9 are preferably much longer than the usual phonograph or dictaphone records and are of such predetermined length as to provide for a program of a given time, as for instance one hour each.

The program records, such as are illustrated by 8 and 9 are provided at spaced intervals with bands 10 of conducting material, such as copper, encircling the records, the outer surface of these bands being flush with the surface of the record. Translating units 11 and 12 are provided, one for each of the machines 2 and 3, such units being adapted to follow the sound grooves of the records in the common and well known manner. The bands 10 .are provided with unmodulated grooves so that the movement of the translating .units will not be interrupted in the course of its travel from one end of the record to the other in the usual Figure 3 illustrates in detail one of these translating units, including the diaphragm housing 13, a needle l l and the supporting arm 15 which slide along the shaft 16 mounted on the machine 2 directly to the rear of the record 8. Carried by the diaphragm housing 13 of the translating unit is a contact brush 17 adapted to ride on the periphery of the record as the latter is rotated. A second contact brush 18, carried by an arm 19 mounted at one end on the slidable support- .ing arm 15, also rides on the periphery of the record 8 at a point diametrically opposite that of the brush 17. The function of these brushes will be described in detail later.

The translating unit is provided with what is commonly known in the trade as a magnetic pickup, indicated generally at 20 and consisting of well known means for convertin the vibrations of the diaphragm in the reproducing unit, caused by the passing of the needle 13 through the sound grooves on the record 8, into electric impulses which are impressed upon the carrier wave of the broadcasting apparatus 1 whereby such car- 50 rier wave is modulated in accordance with the sound recorded on the record 8.

Referring again now to the general purpose of this invention, namely, that of simultaneously broadcasting the same program from a plurality of broadcasting stations, such programs being recorded on records and each broadcasting station being described, it will be understood that of necessity each of the stations must begin their broadcasting at the same instant and that therefore their translating machines must be started simultaneously. For this purpose, the station designated as the master casting stations arate broadcasting unit 21, capable of broadcasting waves of a relatively high frequency and under the control of a switch 22. Each of the individual broadcasting stations is provided with a radio receiving set indicated generally at 23, preferably tuned to the high frequency wave of the broadcasting station 21. These receiving sets 23 should be so tuned and then locked so that the receptlon of the signals from the broadcasting station 21 will be insured.

Mounted across the output 24 of the receiving set 23 is a frequency meter 25, the pointer 25 of which when excited is adapted to move to the position on the dial of the meter indicating the frequency of the signals received. The pointer 26 is preferably a conductor and is connected by means of the wire 27 to one side of a course of electricity such as an 110 volt current, and at the point on the dial representing the frequency of the broadcasting station 21, and to which point the pointer or indicator 26 moves when the signals are received in the set 23, there is provided a contact 28 with which the pointer 26 isadapted to close. This contact 28 is connected through the wire 29, magnet 30 and wire 31 to the other side of the 110 volt current.

Pivoted adjacent one end of the magnet 30 is an armature 32, the lower end of which is adapted to engage, and, when attracted to the magnet, adapted to close the switch 33 included in the 110 volt circuit and controlling, through the wires 34, and 51a, the electric motor 4 for the reproducing machine 2. It will be clear, therefore, that with all the various broadcasting stations ready to begin their program, that is with their records 8 on the machines 2 and the translating units 11 placed at the beginning of the records, for instance at the groove or indicating mark 35, the master broadcasting station at the proper instant can upon closing the switch 22 of his high frequency broadcaster excite the receiving sets 23 at each local station which in turn operate the frequency meter 26 to close the circuit through the magnet 30, this causing the armature 32 to move over and close the switch 33 whereby the motors 4 in each local station are started and the reproduction of the sound on the records 8 begun. As before stated, the translated I sound record is passed through the magnetic 'pickups 20 and impressed upon the carrier waves of the broadcasting units 1. In this I manner, it will be understood that the master provided with the translating machines Just broadcaster can by closing the switch 22 simultaneously start all of the local broadon the program. The switches 33 remain closed, and of course the high frequency broadcaster need be operated only long enough to cause the closing of the switches 33, whereupon it can be shut off. broadcasting station, is provided with a sep- After .the starting of the motor 4:, the

sound on the record 8 is translated and the electric impulses which are the converted sound waves pass through the wires 3.6 and 37 to the broadcasting unit 1. At the end of say a fifteen minute period of reproduction, the translator 11 reaches the first copper band 10 on the record 8, at which point the translation of the sound record of course ceases for a given period, controlled by the width of the copper band 10, and simultaneously the brushes 17 and 18 carried by the translator engage such copper band and close a circuit included by the wires 38 and 39 in the 110 volt current, and, also included in which circuits through the medium of wires 40, 41 and 39 is a magnetic relay 42 which when excited through the closing of the said circuit by means of the brushes 17 and 18 engaging the copper band 10, attracts the pivoted armature 43 against the tension of the spring 44. Included in the circuit between the magnetic pickup 20 and the broadcasting unit 1, is a switch 45 connected by the link 46 to the armature 43. It will be clear from Figure 2, that due to the action of the spring 44, this switch is normally closed with the contacts 47 whereby to complete the circuit between the magnetic pickup 20 and the broadcasting unit 1. lVhen, however, the magnet 42 is excited as just described, the switch 45 is pulled to the left in Figure 2 to close with the contacts 48, thereby breaking the circuit between themagnetic pickup 20 and the broadcasting unit 1 and close a circuit through the wires 49 and 37 between a microphone 50 and the broadcasting unit 1. Therefore, during the interval when the translator 11 is passing over the width of the copper band 10 on the record 8, the magnetic pickup 20 is cut off from the broadcasting unit 1 and the microphone 50 is cut into such unit, whereby the local announcer at each of the stations on the hook up may make his announcements. Promptly upon the passage of the translating unit 11 and the brushes 17 and 18, oil of the copper band 10 and onto the next section of recorded sound on the record, the circuit to the magnet 42 will be broken and under the influence of the spring 44, the armature 43 will return to the position shown in Figure 2 resulting in throwing the switch 45 out of engagement with the contacts 48 and back into engagement with the contacts 47. thereby breaking the circuit between the microphone 50 and the broadcasting unit, and again closing the circuit between the magnetic pickup 20 and such unit. It will be understood of course that as many of the copper bands 10 may be provided on the record 8 as are desired, this being arranged in advance and depending of course upon the character of the programs recorded on the record.

In order that there, may be no interruption to the program, when one record has been completed, for the purpose of changing records, each of the broadcasting stations is provided with a second translating machine 3, identical in every respect with the first, upon which a record 9 may be positioned ready for translation when the record 8 on the first machine has been completed. Means are provided for automatically starting the second machine at the proper time upon the completion of the translation of the first rec- 0rd 8. This means includes a lever 51 pivoted at intermediate its ends and, during the translation of record 8, the upper end of the lever lying in position to be engaged and moved by the translator unit reaches the end of therecord 8. The lever 51 is a conductor and is properly insulated with the lower end free to make contact with a contact member 53, included in the 110 volt current circuit by the wires 51a, 60, switch 33 and wire 34, whereby when the circuit is broken by movement of the lower end of lever 51 away from contact 53, the motor 4 will stop. As the translator 1.1 moves the lever 51 on its pivot, the lower end of said lever will at the proper time leave the contact 53 11, as the same and pass into engagement with a contact 54 thereby closing a circuit through wires 55 and 51a through the motor 5 in the second machine, to start the same.

The translator 12 on this second machine 3 is also provided with a magnetic pickup 61 connected to the wires 36 leading to the broadcasting unit 1.

Assuming now therefore, that the translation of the sound on the first record 8 has been concluded, the translator 11 passes onto the last copper band, 62, at the end of the record 8, resulting first, as before described, in breaking the circuit between the magnetic pickup 20 and the broadcasting unit and cutting in the microphone 50 with such unit. At this point, the travel of the translator 11 is such as to engage with the upper end of the lever 51 and start rocking it on its pivot to the right in Figure 2. After the time has elapsed for the local announcer to make his announcements, determined by the width of the band 62, the translator leaves the copper band 62 and again engages the record in the unmodulated grooves 63 at the extreme end of the record, these grooves having no sound recorded therein. Upon leaving the copper band 62, the microphone is again out off and the circuit to the broadcasting station reestablished as before described. At the instant this is accomplished the translator 11 has rocked the lever 51 on its pivot just past the center of gravity whereupon the coil spring 64 serves to complete the rocking of the pivotal movement of such lever 51 to bring the lower end of the lever out of engagement with the contact 53 and into engagement with the contact 54, thereby automatically stopping the motor 4 in the first machine and starting the motor 5 of the second machine. Thereupon, the operation of the various units continues exactly as when the first record was being translated, and during this translation of the second record 9, the record on the first machine may be changed and the translator 11 set back to the starting point ready for starting when the translation of the second record has been completed. The translator member 12 on the second machine 3 is provided with brushes identical with those on the translator 11, whereby when the copper bands 10 are reached periodically on the sec- 011d record, the relay 42 will be operated as before to cut off the magnetic pickup and cut in the microphone for limited periods.

Now when the translator 12 reaches the end of the record 9 and its brushes engage the last copper band thereon, it also starts rocking a lever 66 pivoted at 67 outwardly. The lower end of this lever 66 is connected by a link 68 to the lower end of the lever 51 and when the translator 12 again rides ofi' of the copper band 65 and onto the blank I grooves 69 at the extreme end of the record 9, the translator 12 will have rocked the lever 66 far enough so as to pull the lower end of the lever 51, through the medium of the link 68, far enough to cause the spring 64 to exert its tension to move the lower end of the lever 51 away from the contact 54 and again onto the contact 53 whereby the motor 5 is stopped and the motor 4 on the first machine is again started.

It will be obvious that as many records as desired may thus be reproduced and broadcast simultaneously from a plurality of stations, all of them being started at the same instant by means of the high frequency signals controlled by the master station and thereafter automatically controlled by the operation of the machines at each individual station. It will be understood of course that the motors for driving the machines in all the stations will be carefully selected and timed and that the speed of driving the records will be set and maintained identical in the various stations of the hook-up so that the broadcasting of the sound and the announcement periods will coincide in all of the stations.

Of course, many changes may be made in details of apparatus used as well as the method of controlling the various steps and functions without departing from the spirit and scope of my invention. I do not limit myself, therefore, to the exact forms herein shown and described other than by the appended claims.

I claim 1. The method of radio broadcasting comprising the step of simultaneously starting from a single control the translation and broadcasting of a plurality of identical sound records remote from each other.

2. The method of radio broadcasting comprising the steps of broadcasting radio control signals from a single control station, simultaneously detecting said control signals at a plurality of stations remote from each other, and controlling by such detections at said plurality of stations the translation and broadcasting of sound records at each of said plurality of stations.

3. The method of radio broadcasting comprising the steps of simultaneously starting from a single control, the translation and broadcasting of a plurality of identical sound records remote from each other, and simul taneously intermittently interrupting said translations for local announcements.

4. Radio broadcasting means comprising a broadcasting unit, a sound record, means for translating said record, an electric circuit normally closed for carrying the translated sound to said unit, and record controlled means operatively connected between said record and said electric circuit for automatically and periodically opening said circuit during the translation of said record to permit broadcasting unrecorded announcements through said unit.

5. Radio broadcasting means comprising a broadcasting unit, a sound record, means for translating said record, an electric circuit normally closed for carrying the translated sound to said unit, and means on said record and having operative connection with said electric circuit for automatically and periodically opening said circuit during the translation of said record to permit broadcasting unrecorded announcements through said unit, and for automatically closing said circuit after a predetermined time for each announcement.

6. Radio broadcasting means comprising a broadcasting unit, a sound record, means for translating said record, an electric circuit normally closed for carrying the translated sound to said unit, a microphone, an electric circuit normally open between said microphone and said unit, and means on said record for automatically and periodically opening said first named circuit and closing said microphone circuit to permit broadcasting unrecorded announcements through said unit.

7. Radio broadcasting means comprising a broadcasting unit, a sound record, means for translating said record, an electric circuit normally closed for carrying the translated sound to said unit, a microphone, an electric circuit normally open between said microphone and said unit, and means on said record for automatically and periodically opening said first named circuitand closing said microphone circuit to permit broadcasting unrecorded announcements through said unit, said means including electric conductors at spaced intervals on said record, contacts carried by said translator, and a switch in circuit with said contacts controlling said first two named circuits.

8. Radio broadcasting means comprising a radio receiving set, a broadcasting unit, a sound record, means for translating said record and broadcasting the translation thereof through said unit, means for operating said translating means, and means actuated by operation of said receiving set for controlling said translation operating means.

9. Radio broadcasting means comprising a plurality of broadcasting units remote from each other, sound translating means connected to each unit, identical sound records on each translating means, and means for simultaneously starting each of said translating means comprising a single broadcastin unit and a radio receiving set for each of sai translating means, and means operated by said receiving sets upon detection of signals from said single broadcasting unit for controlling the starting of said translating means.

10. Broadcasting means comprising a broadcasting unit, a sound translating device including a magnetic pickup, a sound record operatively associated with said device and provided with spaced conductors, and contacts on said translating device adapted to engage with said conductors, said contacts and said conductors serving to break the circuit between said magnetic pickup and said unit.

PAUL M. TITUS. 

